Redhead FC FC project

[Shadow24v]

Well, i figured i'd start a project thread in the right place. I picked up a 87 N/A FC last spring for a trifling $300. Its a South Carolina car and is virtually rust free. Aside from some major and minor issues, the car seems to be in OK shape. I have the typical leaking sunroof along with a semi-dead motor. This is also my first rotary car/rebuild

The motor will start right up and run, but its eating oil and coolant like a kid eating PEZ. 1/2 a quart of oil in 30 minutes and its a mosquito fogger with the coolant its burning.

Interior is a little rough, cracked vents, a little dirty and the shifter boots need replaced. It also has a dent/scrape on the quarter panel/door but that is minor.

The plan at the moment is to secure a used S5 N/A motor and do a hybrid build consisting of:
S5 rotors/c-weights
S5 Intake
S4 front cover (to retain mechanical MOP)
Ported 6-port irons w/ pineapple inserts
S5 trans
EGR Blockoff

Not sure on the rebuild kit yet, possibly going to go atkins with cryo treated apex, solid corner and side seals.

Second phase after getting the rebuild running and broken in on stock S4 electronics will most likely be a Megasquirt ECU. Not sure if this is going to be the PnP MS (based on the MS-II Extra Microsquirt) or the MS-III (if its out of beta by the time im done)

I have some questions regarding ideas i have for the build.
1) is bridgeporting the aux ports worth the time?
2) What RPM should i limit the motor to after the porting and rotor swap?
3) Is there anything else that can be done to the motor that would be beneficial in a pre-mild turbo build? (retaining S5 rotors on said turbo build)
4) with a header and cat-back exhaust, is there enough pressure to actuate the 5th and 6th ports or do i have to run an electrical or air pump based alternate method?
5) Is there an LSD that fits the N/A rear end? or is the LSD limited to the T-II??

In addition, there are some parts that i will be in the market for used or new (will update as needed )
1) pineapple 6-port porting template
2) header and cat-back exhaust for an N/A 6-port motor
3) Flywheel stop


Advice, input and suggestions welcome and encouraged

[Rx-7fetish]

Originally Posted by Shadow24v

I have some questions regarding ideas i have for the build.
1) is bridgeporting the aux ports worth the time?
2) What RPM should i limit the motor to after the porting and rotor swap?
3) Is there anything else that can be done to the motor that would be beneficial in a pre-mild turbo build? (retaining S5 rotors on said turbo build)
4) with a header and cat-back exhaust, is there enough pressure to actuate the 5th and 6th ports or do i have to run an electrical or air pump based alternate method?
5) Is there an LSD that fits the N/A rear end? or is the LSD limited to the T-II?
Advice, input and suggestions welcome and encouraged

1) only if you dont plan to daily drive it, porting kills idle progressivley, as in the bigger the port the worse the idle
2) Dont know
3) Dont know
4) Any change to stock exhaust will require one of the 2 mods, mostly like the stock exhaust isnt actuating them anymore
5) There are a couple of aftermarket lsd's that will fit, or you could find someone selling the rear out of a gxl model car they have an lsd also that will fit in any na.

[Shadow24v]

Ok, so the streetport template is about the best you can get without adversely affecting idle and drive-ability? I guess that makes sense

Regarding the exhaust - i sorta thought an aftermarket would require alternate methods of aux port actuation. thanks for the confirmation

Hmm, i'll have to look around at the GXL option then. thanks

[project86]

just wire your ports open. thats what i did on my na

[RotaryProphet]

I would remove the 5 & 6 port sleeves entirely, and use some JB weld or similar to build a "ramp" for the air entering the ports, so it's not such a right angle turn entering the chamber. (Like these, but in the port itself instead of the sleeve: http://www.pineappleracing.com/6-por...sertspair.aspx)

I've done this to very good effect on a similar hybrid motor, a GSL-SE 6 port with S5 NA rotors & weights.

[WE3RX7]

Lots of JB weld in the intake --- no thanks.... I'd keep the sleeves in and use the inserts. Those sleeves do help bottom end and fuel mixtures entering the combustion chamber. Its not hard to get to them and clean 'em and once functioning correctly, they're nice to have in an NA car....

[TitaniumTT]

Originally Posted by WE3RX7

Lots of JB weld in the intake --- no thanks.... I'd keep the sleeves in and use the inserts. Those sleeves do help bottom end and fuel mixtures entering the combustion chamber. Its not hard to get to them and clean 'em and once functioning correctly, they're nice to have in an NA car....

This man speaks the truth

Originally Posted by Shadow24v

Second phase after getting the rebuild running and broken in on stock S4 electronics will most likely be a Megasquirt ECU. Not sure if this is going to be the PnP MS (based on the MS-II Extra Microsquirt) or the MS-III (if its out of beta by the time im done)

Stay away from the MS unless you know what you're doind 100% with it or know someone who does. I am NOT a fan of it at all but there are people on here that use it an know it well and are professional - Rotary Prophet comes to mind

Originally Posted by Shadow24v

I have some questions regarding ideas i have for the build.
1) is bridgeporting the aux ports worth the time?

Not if you want to drive it on the street

Originally Posted by Shadow24v

2) What RPM should i limit the motor to after the porting and rotor swap?

Should follow the rotors - S5 = 8k but in reality you'll run out of breath before that on a "street" turbo motor. 8k+ you should think about balancing. Wish I had actually, but I was too impatient.

Originally Posted by Shadow24v

3) Is there anything else that can be done to the motor that would be beneficial in a pre-mild turbo build? (retaining S5 rotors on said turbo build)

I would think twice about doing that, especially with an MS. If you had something that was known to control the ignition properly and accurately then I would say go for it, but personally I don't trust the MS, maybe becuase I've never used it buttttttt like I said, Talk to Rotary Prophet, he seems to be the only one who really knows his shit about the MS

Originally Posted by Shadow24v

4) with a header and cat-back exhaust, is there enough pressure to actuate the 5th and 6th ports or do i have to run an electrical or air pump based alternate method?

Nope, not enough, figure something else out and don't just wire them open either.

Originally Posted by Shadow24v

5) Is there an LSD that fits the N/A rear end? or is the LSD limited to the T-II??

GXL or even better, grab a Torsen from a Miata, you will NOT regret it I promise. Between that rear and the no rear bar, my ass is perfectly predicatble..... even though it gets way too loose too easy but what can ya do about that

[Shadow24v]

Titanium -

I was planning on keeping the aux sleeves anyways. everything i read said that they are a good thing to keep on an N/A build.

Regarding the MS, I have already built and tuned an MS-II v3.0 running the MS-II Extra code for my DD car (92 Sundance Duster with an 01 eclipse v6 running EDIS,mid to high 20s mpg mixed driving, close to or above 30mpg if i blow the whole tank on the highway and ~200ish WHP, 14.712@92.99mph with a crappy 2.1 60')

Why would brigeporting the Aux ports hurt daily driving? don't they open at 4000+rpms? I was thinking a bridge on the aux ports for higher RPM flow while retaining a streetport on the primary and secondary ports...

Also, would running a 4-port center housing for larger primaries adversely affect low end power?

Balancing is being figured in to the build due to the mix-and-match nature of the motor


a Miata diff will fit the N/A rear end and axles? that makes life simpler

[SouthSideSlider]

about the aux bridge lisin to TitaniumTT I beleive it was one of the many things me and him bumped heads over but hes right. also on my current car the aux ports open at ~3200rpm.

As For MS the volvo guys swear by them.(745T owner)

now you could setup and electric actuator(thinking window motor rod setup keep the motor and survo away from the exhast), and RPM switch so you could set the RPM you want your AUX ports to kick in.

if porting i think a large streetport on you aux ports and a mild streetport on your mains might work better then a full aux bridgeport.

[Shadow24v]

south - thanks for the input.

I was thinking of one of the programmable MS outputs to trip a relay for the actuators, but not sure how that would work out just yet.

i was looking at the Pineapple 6-port template for use on my motor build. I'm wondering if there's more room on the aux ports for a slightly larger port with that template or not *shrug* Good point on the aux bridgeport. I want to keep this DD-able so i'll stick with the "streetport" approach (which should help when the turbo gets added later )

[Shadow24v]

here are the pics and vid i mentioned

[Shadow24v]

Well, got to spend 3 days with the 7 this weekend. Got the motor pulled and almost ready to tear apart. Had to "persuade" the crank bolt to loosen up (3' breaker bar and a jammed flywheel works ) and the flywheel nut needed a 5'-6' pope on a breaker bar + gravity to finally pop it loose.

It looks like the rear seal was leaking and i found a piece of metal embedded in the flywheel side of the clutch. Also looks like the PP/FW have some discoloration to them. Can the stock flywheel be resurfaced? I'm thinking about seeing how much a rebuild kit for the trans will cost or whether to look into the miata gear set swap. Hoping to find out soon what the motor is hiding inside. (good compression but coolant/oil consumption) Any input or observations welcome

On the lookout for S5 N/A rotors/counterweights and VDI intake as the S5 motor i had lined up fell through

[project86]

so then im assuming that the torsen lsd from the miata is handling 400+ rwhp then titanium? thats good to know.... hmmmmm.... i like forums....

[Shadow24v]

Got the ports back from hot tanking and made some interesting discoveries: the motor has been rebuilt before. The crank pulley bolt was lathered in blue loctite and the center iron is DEFINITELY newer than the front and rear irons. I measured the wear on the irons and the center and rear irons only came up with .002-.003 step wear max. the front iron came up with .004 step wear Is this beyond the limitations of lapping? How much can you take off the irons with lapping and still be OK? If they aren't able to be lapped due to wear, i am working on a deal for an S5 long block to use so hopefully i can use those parts...

the rotors also seem to have a lip of sorts on the back part of the apex seal groove. Is this normal wear? the apex clearances were in spec before the rotors were totally pulled apart.

Also, can you lap the housings to eliminate pitting around the water seals? (if you look at the pics, i doubt my housings are useable anyways...)


Rear Iron (notice how rusted the hose nipples are)




Center Iron (notice how new and fresh the nipples are and the general condition of the iron)


Center vs rear


Front Iron (worst step wear of .004)



Front vs center

[Shadow24v]

Rotors (lip edge and weights)

Lip i mentioned before

Rear rotor

Front rotor


Rear housing (im gonna guess bad wear but some input on the wear and wear patterns would be appreciated)











Front Housing (again, bad wear and im guessing an unusable housing )